The fact that vine as a name and at least some vines are still at least somewhat prevalent online, makes me think that vine literally was "already" the next big thing and twitter just completely misread the room.
yeah, people are still reconnecting with vine creators, on TikTok. You can see in the comments, a video came up on the user's feed and they were compelled enough to be like "are you so and so from vine!?" Vine was killed half a decade ago.
And YouTube. Some of the biggest commentary channels used to be Viners.
The fact that it was shut down when it was is testament to how badly Twitter misplayed their hand with it. Every single creator flocked to whatever platform would take them at the time.